1. Field of the Invention
The present invention relates to an endoscope hood which is attached to a distal end portion of an endoscope insertion portion by press fitting.
2. Description of the Related Art
In order to facilitate focusing of an endoscope observation image and stable observation, observation may be carried out with a cylindrical endoscope hood being attached to a distal end portion of an endoscope insertion portion.
As such a hood, for example, Jpn. Pat. Appln. KOKAI Publication No. 2001-224550 discloses a technique which prevents a protrusion portion which protrudes in an observation visual field direction on a distal end of a hood main body from being displayed on an endoscope observation image. The hood according to this technique has at least a part of the protrusion portion formed into an angular shape along an outer edge of an observation visual field or a shape that an end is partially cut so as to prevent an observation visual field from being obscured.
The endoscope hood has a hood main body formed of a soft material such as a rubber. Such a hood is fixed by elastically deforming the cylindrical hood main body and press-fitting a fitting hole portion of the hood main body to a distal end portion of the endoscope insertion portion. Therefore, it is possible to attach a hood with a size other than an appropriate size such that an inside diametric dimension of the fitting hole portion (inner peripheral surface) of the hood main body fitted onto the distal end portion of the endoscope insertion portion is set to an appropriate dimension with respect to an outside diametric dimension of the distal end portion of the insertion. For example, even if an outside diameter of the distal end portion of the insertion portion to which the hood is attached is too large or too small with respect to a standard dimension, since the material of the hood is elastically deformed, the hood can be attached to the distal end portion of the endoscope insertion portion.